Adenosine is a substance that may exhibit various physiological actions when it binds to a receptor on a cell surface. The adenosine receptor on the cell surface belongs to G-protein-coupled receptor family, and it is classified into A1, A2a, A2b and A3. Among them, the adenosine A1 and adenosine A3 receptors are coupled with Gi-protein and the activation thereof results in lowering of the intracellular c-AMP level. In addition, adenosine A2a and adenosine A2b receptors are coupled with Gs-protein and the activation thereof results in heightening of the intracellular c-AMP level. These 4 kinds of adenosine receptor subtypes each have been cloned.
A variety of studies about agonists and antagonists which may work on each of the above adenosine receptor subtypes have been already reported. Among them, the adenosine A2a receptor agonists have been reported not only to exhibit the potent antihypertensive action and to be useful as above-mentioned drugs such as an antihypertensive drug, a medicament for treating/preventing cardiac or cerebral ischemic disease and antiarteriosclerotic drug, but also to exhibit an ocular hypotensive action (see J. Pharmcol. Exp. Ther. 320-326, 273 (1995).
WO 2005/105778 discloses cyanopyrimidine compounds which are an adenosine A2a receptor agonist. However, WO 2005/105778 does not disclose any specific cyanopyrimidine compounds like the present invention.